According to “The United States Food and Drug Administration (FDA),” castor oil is "generally recognized as safe and effective (GRASE)” for over-the-counter use as a laxative, with its major site of action, the small intestine.

Therapeutically, modern drugs are rarely given in a pure chemical state, so most active ingredients are combined with excipients or additives.

For instance, Cremophor EL is a registered trademark of BASF Corp. for its version of polyethoxylated castor oil. It is prepared by reacting 35 moles of ethylene oxide with each mole of castor oil. Cremophor EL is a synthetic, nonionic surfactant. Its utility comes from its ability to stabilize emulsions of nonpolar materials in aqueous systems. Cremophor EL is an excipient or additive in drugs. Therapeutically, modern drugs are rarely given in a pure chemical state, so most active ingredients are combined with excipients or additives such as Cremophor EL.

Castor oil, or a castor oil derivative such as Cremophor EL, is added to many modern drugs, including:

·         Miconazole, an anti-fungal agent

·         Paclitaxel, a mitotic inhibitor used in cancer chemotherapy

·         Sandimmune (cyclosporine injection, USP), an immunosuppressant drug widely used in connection with organ transplant to reduce the activity of the patient's immune system

·         Nelfinavir mesylate, an HIV protease inhibitor

·         Saperconazole, a triazole antifungal agent (contains Emulphor EL -719P, a castor oil derivative)

·         Prograf, an immunosuppressive drug (contains HCO-60, polyoxyl 60 hydrogenated Castor oil)

·         Xenaderm ointment, a topical treatment for skin ulcers, is a combination of Balsam Peru, Castor oil, and trypsin

·         Aci-Jel, a gel used to create or maintain the acidity of the vagina (comprises acetic acid/oxyquinoline/ricinoleic acid – vaginal)

·         Polyethylene glycol (PEG): Peg-40 is a hydrogenated castor oil used in pegylation. Pegylation is now an established method for increasing the circulating half-life of protein and lipsomal pharmaceuticals. Pegylation agents are beneficial for patients with cancer.

·         Emulphor: A polyethoxylated castor oil drug vehicle.

·         Taxol (paclitaxel)

·         Sandimmune (cyclosporine injection, USP)

·         Diazepam injection; superseded by lipid emulsion alternative (Diazemuls)

·         Vitamin K injection

Anti-cancer Drugs

·         An obstacle to successful chemotherapy and cancer treatment is multidrug resistance (MDR). Cremophor from castor oil is a chemomodulator and a MDR reversing agent used in anti-cancer drugs.

·         Teniposide (VM-26) has been widely used in the treatment of small cell lung cancer, malignant lymphoma, breast cancer, etc., and the main ingredient of VM-26 solvent (vehicle) is PECO (Cremophor).

·         Cremophor minimizes the negative effects of radiation chemotherapy.

·         Cremophor EL is a Castor oil surfactant used as a vehicle for formulation of a variety of poorly water-soluble agents, including paclitaxel. The efficacy of paclitaxel against some tumors may be aided by its administration in a vehicle solution containing Cremophor.

·         Fulvestrant is a pure antiestrogen. In in vivo and in vitro breast cancer models, fulvestrant has anticancer activity at least as good as tamoxifen, and is superior to tamoxifen in some models. Fulvestrant requires intramuscular administration in a proprietary formulation of Castor oil and alcohols.

Antifungal Drugs

·         Undecylenic acid is the active ingredient in over-the-counter medications for skin infections, and relieves itching, burning, and irritation. For example, it's used against fungal skin infections (mycosis) such as athlete's foot, ringworm,           Candida albicans, etc. It's also used in the treatment of psoriasis. Undecylenic acid also has anti-bacterial and anti-viral properties that are effective on viral skin infections such as the herpes simplex virus, cold sores, warts, etc.

·         Cutaneous alternariosis can be treated with miconazole and 10 ml of Cremophor EL.

Heart & Blood Pressure Drugs

Digoxin with Cremophor is used to treat certain heart conditions. The diluent Cremophor contributes to the antiproliferative effects of the taxane paclitaxel.

Human Immunodeficiency Virus (HIV) Protease Inhibitors

Saquinavir (SQV) with Cremophor is a HIV specific protease inhibitor.

Organ Transplant Drugs

Cyclosporin is considered to be the best immunosuppressive molecule in transplantation (10A) and it gets help from its vehicle, Cremophor.

Use of Castor Oil to Encourage Onset of Labour

Castor oil has a long history of being used by women to encourage the onset of labour during pregnancy. It is thought to act in one of several possible ways. By creating strong and spasmodic cramps of the intestines (which lie around and above the uterus at the end of pregnancy) it might cause a reflexive cramping and spasms of the uterine muscle, which might then turn into labor. It might also work by having a dehydrating effect, which causes uterine irritability and then labour. It could also encourage the onset of labour by stimulating the release of prostaglandins from the inflammation of the intestines. And, lastly, it may have no real connection to the onset of labor at all, and be merely an unpleasant placebo.

While the effectiveness of castor oil to encourage the onset of labor is scientifically questionable, it is generally considered safe, although there are some who believe that it increases the risk of meconium passage in the infant. This application of castor oil has not been well studied – surprising considering how long this old remedy has been in use.